Internal-combustion engine



Oct. 29, 1929. A G, SHERMAN 1,733,431

INTERNAL COMBUSTION ENGINE Filed Aug. 15 1925 3 Sheets-Sheet `1 agg, A.

I 61mm Oct. 29, 1929. A. G. SHERMAN 1,733,431

INTERNAL COMBUSTION ENGINE Filed Aug. 15 1925 3 SheeVts-Sheerl 2 Oct. 29, 1929.

A. G. SHERMAN 1,733,431

INTERNAL COMBUSTION ENGINE Filed Aug. l5 1925 5 Sheets-Sheet 55` inventor ARTHUR G. SHERMAN `it is necessarfy Piuma oa. 29, 192s UNITED STATES PATENT OFFICE Application lled August 15, 1985. Serial lo. 50,488.

This invention relates to internal combustion engines and to carbureting and fuel injecting apparatus for such engines.

While the invention hasfeatures applicable to both 'four cycle and two cycle eng1nes,'its use is particularly desirable with engines of the two cycle type in view of its elimination of certain objectionable features of such engines. It is well known that two cycle engines are in many respects superior to those of the four cycle type owing to the provision by the former for twice the number of power strokes afforded by the latter. Thus, for a given development of power, a two cycle engine may be smaller and lighter than a four cycle engine and will develop such wer more steadily and flexibly. Also, the a sence of cam shafts and cam actuated valves simpliiies the construction of two cycle engines and lessens both their original cost and their upkeep expense, as compared to four cycle engines. Despite these numerous advantages of the two cycle type, the four cycle engine is at the present time far more extensively used, this being due primarily to the fact that the present two cycle system of delivering an explosive mixture to the crankcase and thence to the cylinders is not satisfactor particularly under starting conditions. Before such an engine is in condition to start, to crank the shaft repeatedly in order to ll the crank case with a combustible mixture. This is laborious and particularlyso in cold weather when the fuel tends to ra idly condense as the mixture is introduced mto the crank case. Even after the engine has warmed up and is running normally, there is suicient crank case condensation to prevent delivery of a constantvalue mixture to the cylinders.

It is one object of the present invention to eliminate these objections by delivering an explosive mixture directl from a carburetor to the cylinder or cylin ers) of a two cycle englne, rather t an through the crank case,

and to com rees-air in the crank case for delivery to t e carburetor rather than compressing the mixture therein, as is now the usual practice.

Another object 1s to provide an lmproved means for introducin a charge under superatmospheric pressure into the cylinders o internal com ustion engine, regardless of its number of c cles.

Still anot er object is to provide a two cycle engine in whlch compressed air is dellvered to the air inlet of a carburetor so that the resulting mixture may be delivered under pressure to the engine c linders,-and to reduce the necessary capacity of the blower or other air compressing means by discharging therefrom into the crank case ofthe engine and utiliziin piston travel of the engine to further buil up the air pressure.

A still further object is to deliver the fuel mixture to a multi-cylinder two cycle engine under a more uniform pressure than is permitted by present constructions.

The invention seeks also to locate the spark-forming device of a two cycle cngine so as to insure the spark being formed 1n proximity to a pure fuel mixture.

Utilization of the crank case of a two cycle engine as a lubricant container is also a feature of the engine, as is delivery of air from said crank case to the carburetor andseparation of lubricant from said air in the course of such delivery.

Automatic prevention of rotation of the engine in the wrong direction when being started is also an aim of the invention.

These and various other objects the invention attains by the construction hereinafter described and illustrated in and accompanyindrawing, wherein:

ig. 1 is a front view of a two cycle engine equipped with the improved charge forming and injecting means.

Fig. 2 is a rear view of the same.

Fig. 3 is a view of said engine in sectional elevation, taken on line 3 3 of Fi 1.

Fig. 4 is a detail view in side eavation of the ignition timer, showing a provision for breaking the ignition circuit, in the event of initial turning of the motor in the wrong direction.

Fig. 5 is a top view of the timer casing with its cover removed.

Fig. 6 is a front view of an alternative -form of the engine.

1' port 7 and exhaust port 8 arrangedl in the compartments are included in a lubricant circulationsystem. Each cylinder has an inlet usual substantially o posed relation, sofas tobe uncovered by t e piston as the latter com letes its power stroke. The intake ports 7 o the several cylinders are adapted .to receive afuel mixture from a common mani# fold 9 and the several exhaust ports 8 of the engine discharge to a common manifold 10.

A carburetor comprising a mixing passage 11 and a float chamber 12 has a discharge connection from said passage to the .manifold 9. Fuel is delivered from said lioat chamber to the assage 11' by a suitable nozzle 13 controlla as 1s common practice, by needle' valve 14. Air under superatmospheric pressure is delivered to the mixino' passage 11 through a pige 15 from a combi-ned air lmanifold and lu ricantseparator 16. Air,

carrying in suspension a certain amount of lubricant, is delivered into said manifold from the several compartments of the crank case 3 by way of ports 17, controlled by check valves 18, opening under the air pressure set up by the power strokes of the pistons, and closing against any back-iow.

Within the manifold 16 a series of alterf nately arranged upstanding baiiies 19 and depending' bailes 2O form a tortuous air as sage within which any lubricant entralned by the air tends to fall out of suspension.A Such lubricant then drains through suitable outlets 21 in the floor of said manifold into a chamber 22 formed by the lower portionof the manifold 16. From said chamber a pipe 22, controlled by a check valve 22, delivers the lubricant to the engine shaft bearings,

from which the excess returns into the crank.

case.

In the carburetor practice now generally followed, atmospheric pressure is maintained. in the float chamber and the differential between such ressure and that reduced presi sure induces by the engine 'in the mixing passage is relied upon to maintain a fuel discharge to the mixing chamber from the float chamber. A departure from such practice is essential in the present invention, since superatmospheric pressure exists in the mixing passage. The float chamber 12 is not open to the atmosphere but is connected by an air duct 22 to the inlet portion of the passage 11 and air is also delivered to the base .tively the air delivery to said passage and the mixture How therefrom. l

For admission of air .under atmospheric pr ssure to the crank case, each compartment of t e latter is providedwith a port.23, controlled by a check valve 24 preventing outiiow. Provision is also made for delivering air under superatmospheri'c pressure to the crank-case. Thus each cylinder 1 is formed with a port 25 closed by the corresponding piston except when the latter is in itsraised limiting position. In such position of the piston, said port is uncovered to admit air under superatmosphericpressure to the corresponding crank casev com artment. The several ports 25 are connecte by branches 26 with a manifold 27 to which leads the outlet pipe 28 of a blower 29, or other source of compressed air. The inlet pipe 30 of said blower terminates in an air cleaner 31, of any suitable construction, and a branch 32 from the pipe 30 delivers air to a manifold 33 from which the several ports 23- open to the crank case. l

Preferably a liquid fuel tank 34, whichhas the usual fuel delivery connection 35 to the float chamber 12, is connected as indicated sage of the carburetor will be substantially balanced. Thus the existence of superatmospheric pressure inthe oat chamber will not interfere with the How of fuel to said .a contact -arm 42 is pivoted to the arm 40.

Said contact arm is adapted terminally to successively bear upon a series of contact buttons 42a when the shaft 38 is driven, said buttons being carried by the cover 43 of the timer casing.

When the direction of rotation of the timer shaft is normal, as indicated bythe arrow in Fig. 5,`the contact arm 42 is included in the ignition circuit 44 through .engagement of said arm with a terminal 45 carried by the arm 40. If, however, upon startingA of the engine, it tends to turn ina backward direction, the contact arm 42, is swlmg to the position shown in dash lines in Fig. 5, and the -at 3 6 to the pipe 15 so that air pressure existing in said tank and in the mixture pas- ,piesa 'l 1s mounted in the cylinder -wall a ignition circuit is broken, stopping the engine.

`with the cylinder wall 'a pocket 47, and the spark lug 6, as is best seen in Fig. 3, occu- 'g ly desirable position with respect to this pocket. That is to say,- the s ark plug the head of the cylinder and is ad acent to the line of reciprocation of said ba e so that when the piston hascompleted its compression stroke, the pocket 47, containinga-portion of the charge, substantially uncontaminated byproducts of combustion, is close adjacent to said s ark-plug, and ignition ofthe mixture when t e spark 1s formed is thus rendered ractically certain. l

In t e operation of the described engine,

l the'blower 29 is driven in any suitable man' ner, vas for example, through a belt connec- 5 tion 37 to the crank-shaft, and said blower maintains a constant pressure of air in the manifold 27. On the up-stroke of any piston 2, air is drawn into the corresponding crank case compartment through the ort 23 so that upon completion of such stro e said compartment is full of air at substantially atmospheric ressure. lIn terminating its up; stroke, t e piston uncovers the corresponding air port 25, permitting a rush of air under superatmospheric pressure froml the manithe corresponding port 1 oase.

fo1d'27 into the compartment below said piston. Thus, when the piston begins its downstroke, it encountersv air under superatmospheric pressure and further builds up such crank case compartment escapes by way of within which it 1s freed from any lubricant that may7 have escaped with it from the crankince in a multi-cylinder en 'ne, at least one piston thereof is always escending, it is evident that delive of compressed air to the manifold 16 will substantially continuous and will further be proportioned to the dischar e of air from said manifold to the engine cy inders by way of the (pipe 15, the mixin passage 11, the manifol 9, and the ports v By thus reventing the pistons on their suction strokes, from effecting any drop of pressure in the manifold 16 and in the deliving the entire period 'that the corresponding intake ports are uncovered, than is possible in` the present construction of two-cycle` engines. As is 'wellknown, there is `a declded i advantage in delivering the chargeto the jacent to to the manifold 16v cylinders under a pressure sustained throughout the charging period, the expulsion of the spent combustion products being under such conditions more complete, and the tenden ofthe mixture to comming: with such r ucts being decreased. a fuller. c arge is, under such conditions, delivered to the cylinders. f l

There is a decided advantage in delivering air from the lblower 29 to the crank case an thence to the carburetor rather than direct to carburetor. This arrangement 'permits use of the crank case, as a compression chamber within which the initial-compression of air eie ed by the blower is considerably raised by the pistons, on their power strokes. By thus producing a first sta e of air compression by the blower and a hlglier sta of compression by the engine pistons, a lower of pression chamberv for the explosive charge,

prevents including the crank case in a lubricant circulation system since the lubricant would commingle undesirably with the charge. Use of the crank case for compression of air, unmixed with fuel, as provided for by the present invention, does notprohibit circulation of :lubricant throu h the crank case, since separation of the lu ricant from the air before delivery of the latter tothe carburetor -is readily accomplished. It is to beunderstood that in the dlsclosed circulation system, the air ressure in the manifold 16 is greater than t at in any crank case compartment when the piston above said com. partment is making its compression stroke and at such times the valve 22 will unseat and oil will f iow to the bearings in said compartment. When the pressure in any compartment exceeds that in the corresponding pi e 2 2 the valve 22" will seat.

igures 6 and 7 show an alternative form of the engine similar te the construction already described except as regards admission of the charge to the engine cylinders. As shown in said figures, the upper portion of each cylinder is restricted as indicated at 48 to form a central intake rt for the explosive mixture and around sa1d port is formedan annular passage '49 to which the mixture is delivered as indicated at 50 from a manifold -51, common to all of the cylinders. The flow ofthe mixture from the passage 49 to the port 48 is controlled by a valve 52 of ring form, preferably havin the nature of a sheet metal sta-mpin Sai valve seats downwardly lupon t e annulus which forms the Vwi passage 49, the central opening of the valve registering with thev port 48, and a plurality of coiled springs 53 may be located within the passage 49 to urge said valve to 1ts seat. The water jacket of the cylinder projects above the annulus 49 as indicated at 54 and is screw threaded to receive a plug 55 which together with the annulus 49 forms a chamber 56 for the valve 52. In the plug 55 is centrall mounted a spark plug, or t e like, 57, whic forms aspark gap 57* within the valve chamber 56. The piston 58 omits the baille member employed in the first described form of the engine, the piston top being preferably convex as shown. Since the remaining features of this construction conform to the description of Figures 1-5, these features require no further description in this connection.

In the operation of this modified construction, when the piston isat the lower end of its stroke, as is indicated in dash lines, and the exhaust port 59 is uncovered, the pressure above the piston immediately drops to such an extent that the pressure existing in the annular passage 49 exceeds that within the valve chamber 56, so that the valve 52 is raisedfrom its seat and the mixture rushes into the cylinder from said passage through the port 48. On the up stroke of the piston, the resulting compression produced above the piston soon raises the pressure in excess of that of the mixture inl the-passage 49 whereupon the valve 52 seats, due to said pressure differential, to the springs 53 and to gravity, and during the remainder of the compression stroke the relativel high ressure produced above said valve olds t e same firmly seated. Duringthe power stroke, the pressure of the exploded charge also acts to hold said valve firmly to its seat until the piston completes said stroke and uncovers the exhaust port, thus relieving downward ressure upon said valve. The described cyc e is then repeated.

It is an advantage of this alternative construction that the charge is admitted to the cylinder at the opposite end thereof to that from which the exhaust escapes so that the incoming mixture may more readily drive out the exhaust gases without being appreciably contaminated by the latter. Also the described arrangement permits a very rapid delivery of the mixture into the cylinder since `the port 48 is oflarge capacity and provision is-made for. a flow of the mixture into said port around its entire periphery.

A still further advantage of this construction lies in thel fact 'that the valve seat is readily machined, and that the valve chamber is readily accessible for the purpose of inspection orlreplacement of parts. Location of the coiled springs 53 within the intake passage 49 is very important in avoiding an overheating and resulting detempering of said springs.. In the specified location, said springs derive a cooling effect both from the incoming charge and within which the annulus 49 is immersed. The formation of the valve 52 as'a sheet metal stamping is importantfrom the viewpoint of low cost quantity production. Preferably the wall of the valve casing 56 is ribbed vertically as indicated at 60 to guide the valve in its seating and unseatingomovement and lugs 61 are formed upon the ttom of the plug 55 to space the valve 52 from said plug in its raised since even though some residue of the latter may-remain when compression of the mixture begins, such residue is not likely to be carried up into the chamber 56. It is to be noted that the disclosed mountin of the valve 52 with relation to the water jac et is highly favorable to rapid cooling of said valve by conduction of heat from the valve to its seat and thence to said jacket.

What I claim is:

1. In an internal combustion engine, a cylinder having an air inlet port, a plston reciprocatory in said cylinder, and uncovering said lport substantially at the termination of its compression stroke, a crank shaft actuable by said piston, a crank case housing said shaft and having a port for the admission of air under atmospheric pressure, a .check valve preventing t e outfiow of air through said port, means for delivering air under superatmospheric pressure to said piston-controlled port, a passage leading from the crank case to the cyhnder, and means for carbureting air flowing through said passage.

2. 'In an internal combustion engine, a combination with a plurality of cylinders, and a plurality of pistons reciprocatory in said cyllnders, a crank shaft actuable by said pistons, a crank case housing said shaft, and forming separate compartments individually opening directly into said cylinders, each of said compartments having an inlet for air at atmospheric pressure, means for delivering additional air at superatmospheric pressure into each compartment substantially at the termination of the compression stroke of the corres onding piston, a manifold with which eac of said compartments has discharge connection, check valves preventing return flow from said manifold to the crank case, and means for deliverin air from said manifold to the several cylin ers of the engine, and for carbureting such air. 1

om the water jacket lll) n manifold, a mixture de 8. In an internal combustion engine, a plurality of cylinders, pistons reciprocatory therein, a crank shaft actuable by saidpisto a crank case housin said crank shaft,y an further forming a ubricant reservoir, said crank case forming com artments in individual communication with said cylinders, each of said compartments having an air inlet and an air outlet, a manifold in communicationl vwith the air outlets of said compartments, lubricant separating means within said very manifold in communication with the several cylinders, a passage leading from the first mentioned to the second mentioned manifold, and means for carbureting air flowing through said passa e.

4. n an internal combustion engine, a cylinder, a piston reciprocatory therein, a crank shaft actuable b said piston, a crank case housing said sha t and opening into the lower end of said cylinder and ported for the induction of air, substantially at atmospheric pressure, responsive to the compression stroke of said piston, means for introducing an additional charge of air under super-atmospheric pressure into the crank case substantially at the termination of the com ression stroke of the piston, means controlle by the piston for delivering air from the crank case to the compression chamber of the cylinder, and means for carbureting the last mentioned air in the course of its delivery.

5. If an internal combustion engine, a cylinder having in its lateral wall a port for admission of air and also having in its lateral wall a port for admission of a fuel mixture,

'a piston reciprocatory in said cylinder adapted to uncover said airy admission port substantially at completion of its compression stroke and to uncover said fuel inlet port substantially at completion of its power stroke, a crank shaft, a drive connection to said shaft from said piston, a crank case h ousing said shaft and ported for induction of air at substantially atmospheric pressure responsive to the compression stroke of the piston, means for delivering air under super-atmospheric pressure to said air inlet portof the cylinder, a passage leading from the crank case to said fuel inlet port of the cylinder whereby the ilowfrom the crank case to the cylinder is induced by the compression of air in the crank case, and means associated with said passage for carbureting the air flow therethrough.

6. In aii internal combustion engine, a c 1- inder havin in its lateral wall a port or admission og air and having a fuel inlet ort, a piston reciprocatory in saidcylinder, a apted to uncover said air admission port substantially at completion of its compression stroke, a crank shaft, a drive connection to said shaft from said piston, a crank case housing said shaft and ported for induction of 'air at substantially atmospheric` pressure responsive to the compression stroke of the piston, means for deliverin air under superatmos heric pressure to sai air inlet port of the cy inder, a passa leading from the crank case to said fuel in et port of the cylinder whereby the flow from the crank case tothe cylinder is induced by the compression of air inthe crank case, and means associated with said assage for carbureting the air' Vow theret rough. 7. In an internal combustion engine, a cylfinder havin a fuel inlet port, a piston reciprocatory in said cylinder, a crank shaft actuable by said piston, a crank case communicating with said cylinder and housing said shaft, ported for induction of air at substantially atmospheric pressure responsive to the compression stroke of said piston, means for compressing air, a passagev rovi for the delivery of compressed air rom the sstnamed means to the crank case, said piston exercising control of communication f'said passage with the crank case, whereby such communication is normally cut off and is established substantially upon completion of the com ression stroke of the piston, a passa e lea ing from the crank case to said fuel in et port, providing for a flow of air to said inlet port responsive to air compression in the crank case, and means associated with said passage for carbureting the air flowing therethrough. y 8. In -aninternal combustion engine, a cylinder havin in its lateral wall a port for admission o air and having a fuel inlet V rt, a piston reciprocatory in said cylinder a apted to uncover said air admission port su tially at completion of its compression stroke, a crank shaft, a drive connection to said shaft from said piston, a crank case housing said shaft, an air cleaner, an air delivery passage leading from said cleaner and having discharge connection with the crank case, meansl for delivering air under super atmospheric pressure from said cleaner to said air inlet port of the cylinder, a passage leading from the crank case to said fuel inlet port, providing for a flow of air to said inlet port responsive to air compression in the crank case, and means associated with said passage for carbureting the air owin therethrough.

9. In an internal com ustion engine, a plurality of cylinders, pistons reciprocatory in said cylinders, a power transmission member 'ointly driven by said pistons, compartments individually communicating with said c linders, forming air compression cham rs, means for introducing compressed air into eacli compartment u n completion of the compression stroke ofthe corresponding piston, said piston being adapted on itspower stroke to further compress such air, ,an air manifold connected to all of said compartments, means for establishing a flow of air to each of the cylinders from said manifold, and means for carbureting the air in the course of such flow.

10. In an internal combustion en 'ne, a cylinder having a headed end and ormed with an air inlet port, a mixture inlet and an exhaust port in its lateral wall remote from said headed end, means for delivering air under super-atmospheric pressure to said air 10 inlet port, a piston reciprocatory in said cylinder and uncoverin said air inlet port substantially at comp etion of its compression stroke, and uncovering said mixture inlet and exhaust ports substantially at completion of its (power stroke, a crank shaft actuable b sai piston, a crank case housing said sha and ported for induction of air at substantially atmospheric pressure, responsive to the compression stroke of the piston, a passage leading from the crank case to the mixture inlet port, and means for carbureting the air iiow through said passage.

11. The combination with the fuel delivery passage of an internal combustion en ine, of means for driving compressed airgt rough said assage, a car uretor comprising a reservoir aving an outlet to said passage, an air connection to said reservoir lrom a point in said passave in advance of said outlet, and 3o a throttle 1n said passage between said connection point and said outlet.

In testimony whereof I slgn this speciication.

ARTHUR G. SHERMAN.' 

